A. Longitudinal Follow-up of LeFort III Advancement in the Growing Child This research represents the continuation of a previously funded study. Children who have undergone LeFort III advancement before the age of 12 are being studied in order to determined whether 1) there is stability of the advanced midface in the growing child, 2) there is evidence of growth of the advanced maxilla following surgery, and 3) what are the dental relationships when followed longitudinally. The Study will include approximately 50 patients who had LeFort III advancement performed before the age of 12. The assessment, which will include lateral cephalograms and dental analysis, will be continued until the age of 16 in females and 18 in males. Documentation includes occlusal assessment and cephalometric analysis by the orthodontist. B. Definition of the Mandible in Craniofacial Synostosis Syndromes: A Cephalometric Study This study is designed to quantitate the variation in shape and size of the mandible in craniofacial synostosis syndromes. A single lateral cephalogram from each of the 80 patients of equal sex and random ethnic backgrounds will be used. Crouzon, Apert and Pfeiffer syndrome patients will be studied, and the results compared to the investigators' previous study of Treacher Collins syndrome patients. Each cephalogram will be traced and digitized. A medial axis will be constructed for each mandible and compared with controls. Conventional landmark and tensor analyses will be used to compare mandible shapes between the syndromes and with normals.